1. Field of the Invention
The present invention relates to a wobble type fluid pump suitable for use in a refrigeration cycle for a vehicle.
2. Description of Related Art
JP-A-63-94085 discloses a wobble type pump including a rotating member having a slant plane, which is slanted with respect to a shaft and is integrally rotated with the shaft, and a swing member which is connected to the slant plane through a thrust bearing and is swung with the rotation of the rotating member to reciprocate a piston.
In the wobble pump, a swing support mechanism supports the swing member such that it can swing by engaging a bevel gear provided on the rotating member with a bevel gear provided on the swing member. Thus, when a pump is operated, it tends to make noises by the engagement of the teeth of the bevel gears.
JP-A-2-275070 also discloses a wobble type pump. In the wobble type pump, since a swing member is supported by a spherical sliding part at the outer peripheral side of the swing member, the noises produced by engagement of the teeth of the gears is reduced. However, an inertia moment of the swing member is increased, that is, the inertia moment in a rotational direction of the swing member is increased because the spherical sliding part is disposed at the outer peripheral side of the swing member.
Thus, when a shaft rotates at high speeds, the swing member is swung by a force for rotating the swing member around the shaft such that the swing member turns around the shaft to excessively vibrate a piston, which results in presenting problems of making large noises and reducing reliability and durability of the pump at high rotational speeds.
An object of the present invention is to suppress a vibration of a swing member and a movable member such as a piston at high rotational speed in a fluid pump.
According to the present invention, a swing support mechanism includes a first rotating member capable of rotating around a first axis (L1) perpendicular to a center line (Lo) of a shaft. A constraining member is connected to a first rotating member and restraining the first rotating member from rotating around the center line (Lo). A second rotating member is connected to the first rotating member such that the second rotating member rotates around a second axis (L2) perpendicular to the center line (Lo) and crossing the first axis (L1). The swing member is connected to the second rotating member.
Since the swing member is supported by the swing support member such that it can swing in a state where it is prevented from rotating around the center line (Lo), even if the shaft rotates at high speed, the swing member is surely prevented from rotating around the shaft.
Therefore, it is possible to prevent the piston from excessively vibrating, hence to prevent large noises from being made, and to improve reliability and durability of the pump at high rotational speed.